The present invention relates to an improved endoscope construction and more particularly to an endoscope construction including means for controlling the flexure of an endoscope tube especially the rigidity and curvature of the endoscope tube.
The use of an endoscope for diagnostic investigation or other medical intrusion of various body cavities has become an important procedure for physicians. Endoscope devices are known under various medical instrument names; including, flexible cystoscope, flexible neproscope, flexible gastroscope, flexible bronchoscope, flexible choledochoscope, sigmoidoscope, arthroscope, laparoscope and flexible utererscope. Most of the identified endoscopes have a flexible probe or tube which is designed to pass into a curved body passage. The tube typically incorporates a diagnostic or surgical instrument for observation or operation within the body through the tube from outside the body.
In recent years many patents have issued for various types of endoscopes. These patents disclose, for example, use of optical lens or, in recent years, fiber optics to provide for visual diagnosis. Boebel in U.S. Pat. No. 4,503,843 is typical and discloses a device which utilizes a telescope. Seike in U.S. Pat. No. 4,607,619 discloses an endoscope device utilizing a fiber optic or light guide technique. More recently, Arakawa in U.S. Pat. No. 4,651,202 discloses a video endoscope system wherein the diagnostic information is transmitted from the distal end of an endoscope tube via fiber optic fibers to a proximal end where it is transmitted to a cathode ray tube or television.
Endoscopes are also used for performing surgical procedures. A series of patents teach this use of an endoscope including the following:
______________________________________ U.S. Pat. No. Inventor Title Issue Date ______________________________________ 4,137,920 Bonnet Endoscopes 2/6/79 4,607,620 Storz Medical Gripping 8/26/86 Instrument 4,625,713 Hiraoka Instrument Incorporated 12/2/86 in a Resectoscope 4,641,634 Storz One-Hand Hysteroscope 2/10/87 4,653,476 Bonnet Instrument Insert for a 3/31/87 Uretero-Renoscope ______________________________________
There are additional patents relating to the construction and use of the endoscope instruments including the following:
______________________________________ U.S. Pat. No. Inventor Title Issue Date ______________________________________ 4,569,333 Bel, et al Optical Instrument 2/11/86 Including a Focusing Eyepiece and an Endoscope 4,576,435 Nishioka Endoscope Including a 3/18/86 Reflector Related by an Inequality for Uniform 3/18/86 Light Distribution 4,587,972 Morantte, Device for Diagnostic 5/13/867 Jr. and Therapeutic Intravascular Intervention 4,633,855 Baba Endoscope Apparatus 1/6/87 ______________________________________
Generally it is desirable that the endoscope have a flexible tube in order to permit the instrument to follow the circuitous canals and paths defined by body cavities and canals. Many of the prior art references listed above disclose flexible endoscopes.
However, there has remained a need to provide an improved mechanism for controlling the flexure of an endoscope tube in order to more efficiently guide the endoscope through a body cavity. As part of flexure control, there has developed a need to accurately and precisely control the stiffness or rigidity of an endoscope tube. Control of rigidity of the tube is especially critical to facilitate insertion of the tube into a curved body tube or cavity. If the tube is too rigid, insertion may damage the body. If it is too flexible, the tube cannot be properly inserted into the body. As a further part of flexure control, precise control of curvature of the endoscope is desired. These considerations inspired the development of the present invention.